elna/shell/lexer.cpp

125 lines
3.0 KiB
C++

#include "elna/lexer.hpp"
namespace elna
{
source::source(const std::string& buffer)
: m_buffer(buffer)
{
}
source::const_iterator source::begin() const
{
return source::const_iterator(std::cbegin(m_buffer), Position());
}
source::const_iterator source::end() const
{
Position end_position{ 0, 0 };
return source::const_iterator(std::cend(m_buffer), end_position);
}
source::const_iterator::const_iterator(std::string::const_iterator buffer, const Position& start_position)
: m_buffer(buffer), m_position(start_position)
{
}
const Position& source::const_iterator::position() const noexcept
{
return this->m_position;
}
source::const_iterator::reference source::const_iterator::operator*() const noexcept
{
return *m_buffer;
}
source::const_iterator::pointer source::const_iterator::operator->() const noexcept
{
return m_buffer.base();
}
source::const_iterator& source::const_iterator::operator++()
{
if (*this->m_buffer == '\n')
{
this->m_position.column = 1;
++this->m_position.line;
}
else
{
++this->m_position.column;
}
std::advance(this->m_buffer, 1);
return *this;
}
source::const_iterator& source::const_iterator::operator++(int)
{
auto tmp = *this;
++(*this);
return *this;
}
bool source::const_iterator::operator==(const source::const_iterator& that) const noexcept
{
return this->m_buffer == that.m_buffer;
}
bool source::const_iterator::operator!=(const source::const_iterator& that) const noexcept
{
return !(*this == that);
}
token::token(const type of, source::const_iterator begin, source::const_iterator end)
: m_type(of), m_value(begin, end)
{
}
token::type token::of() const noexcept
{
return m_type;
}
const token::value& token::identifier() const noexcept
{
return m_value;
}
const Position& token::position() const noexcept
{
return m_position;
}
result<std::vector<token>> lex(const std::string& buffer)
{
std::vector<token> tokens;
source input{ buffer };
for (auto iterator = input.begin(); iterator != input.end();)
{
if (*iterator == ' ' || *iterator == '\n')
{
}
else if (std::isgraph(*iterator))
{
auto current_position = iterator;
do
{
++current_position;
}
while (current_position != input.end() && std::isgraph(*current_position));
token new_token{ token::type::word, iterator, current_position };
tokens.push_back(new_token);
iterator = current_position;
continue;
}
++iterator;
}
return tokens;
}
}